Sensor device

Abstract

The sensor device includes: a physical quantity voltage conversion element; a differential amplifier; a first capacitor that includes one terminal connected to a first output terminal of the differential amplifier; a comparator; a low pass filter circuit arranged at the first output terminal of the differential amplifier; a control circuit configured to on/off control the physical quantity voltage conversion element, the differential amplifier, the comparator, and the low pass filter circuit; and a logic circuit configured to output a result of operation processing performed on an output signal of the comparator. The logic circuit is configured to: successively verify, in a case where there is a change between a previous logic output and a first logic output, the logic outputs a plurality of times; and output a control signal to the control circuit so that the low pass filter circuit is turned on in a second signal processing period and thereafter.

What is claimed is: 
     
       1. A sensor device, comprising:
 a physical quantity voltage conversion element configured to output a differential voltage in accordance with a magnitude of a physical quantity; 
 a differential amplifier configured to amplify an output signal of the physical quantity voltage conversion element; 
 a first capacitor that includes one terminal connected to a first output terminal of the differential amplifier, and is configured to store an offset voltage; 
 a comparator configured to input a signal obtained by amplifying the output signal of the physical quantity voltage conversion element, and to output a result of comparison; 
 a low pass filter circuit arranged at the first output terminal of the differential amplifier; 
 a control circuit configured to on/off control the physical quantity voltage conversion element, the differential amplifier, the comparator, and the low pass filter circuit; and 
 a logic circuit configured to output a result of operation processing performed on an output signal of the comparator as a logic output, 
 the logic circuit being configured to: 
 successively verify, in a case where there is a change between a previous logic output and a first logic output, the logic outputs a plurality of times; and 
 output a control signal to the control circuit so that the low pass filter circuit is turned on in a second signal processing period and thereafter. 
 
     
     
       2. A sensor device according to  claim 1 , wherein the low pass filter circuit comprises:
 a switching circuit; and 
 a second capacitor connected in parallel to the first capacitor. 
 
     
     
       3. A sensor device according to  claim 1 , wherein the low pass filter circuit comprises:
 a resistive element connected between the first output terminal of the differential amplifier and one end of the first capacitor; and 
 a switching circuit and a second capacitor connected in series between the one end of the first capacitor and a ground terminal. 
 
     
     
       4. A sensor device according to  claim 1 , wherein the physical quantity voltage conversion element comprises a magnetoelectric conversion element configured to output a differential voltage in accordance with a magnitude of magnetic field intensity.